Shock absorber assemblies react between a vehicle frame and vehicle wheel to reduce vibration and shock load inputs and improve ride comfort. A typical shock absorber assembly includes a cylinder that slidably receives a piston coupled to a rod. One end of the rod is mounted to the vehicle frame and the cylinder is mounted to a vehicle wheel structure. A coil spring reacts between a first spring seat on the cylinder and a second spring seat on the rod.
Side loads generated by the coil spring can cause wear and increased levels of friction between the rod and associated cylinder bearings and seals. This can lead to premature failure of the shock absorber assembly.
Further, coil ends of the coil spring can vary from desired configurations. It is preferred to maintain a center of load, i.e. spring pierce point, to be concentric with the rod. However, the coil ends are typically provided with non-parallel coil end planes, which results in dynamically varying spring pierce points. The interface between the coil ends and associated spring seats can often result in non-uniform distribution of load into the spring seats. This can cause the spring pierce point to move out of a desired location, increasing stress on other shock components.
One proposed solution utilizes an adjustable spring seat that allows the spring pierce point to be set for a desired shock absorber operational position, prior to installation in a vehicle. This adjustable spring seat is disclosed in co-pending application Ser. No. 11/327,107, which is assigned to the assignee of the present invention, titled “Static Pierce Point Centering Spring Seat.” While this system has advantages, there is still a need for a system that can dynamically adjust spring pierce point position during vehicle operation to further reduce the effects of side loads.